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We provide a theoretical update of the calculations of the pi0-gamma*-gamma form factor in the LCSR framework, including up to six polynomials in the conformal expansion of the pion distribution amplitude and taking into account twist-six…

High Energy Physics - Phenomenology · Physics 2011-03-22 S. S. Agaev , V. M. Braun , N. Offen , F. A. Porkert

We argue that the recent BaBar data on $\gamma \to \pi$ e.m. transition form factor at large photon virtuality supports the idea that pion distribution amplitude (DA) is close to unity with $\phi_\pi^\prime(0)/6\gg 1$ at a normalization…

High Energy Physics - Phenomenology · Physics 2009-11-10 M. V. Polyakov

We revisit $F_\pi(Q^2)$ and $F_{P\gamma}(Q^2)$, $P=\pi,\eta,\eta'$, making use of the local-duality (LD) version of QCD sum rules. We give arguments, that the LD sum rule provides reliable predictions for these form factors at $Q^2 \ge 5-6$…

High Energy Physics - Phenomenology · Physics 2013-03-15 Irina Balakireva , Wolfgang Lucha , Dmitri Melikhov

In this third paper of a series dedicated to a dispersive treatment of the hadronic light-by-light (HLbL) tensor, we derive a partial-wave formulation for two-pion intermediate states in the HLbL contribution to the anomalous magnetic…

High Energy Physics - Phenomenology · Physics 2017-05-02 Gilberto Colangelo , Martin Hoferichter , Massimiliano Procura , Peter Stoffer

We derive the dependence of the leading-twist pion light-cone distribution amplitude (LCDA) on a parton momentum fraction $x$ by directly solving the dispersion relations for the moments with inputs from the operator product expansion (OPE)…

High Energy Physics - Phenomenology · Physics 2022-08-31 Hsiang-nan Li

In this paper, a study of light-cone distribution amplitudes for p-wave heavy mesons is presented in both general and heavy quark frameworks. Within the light-front approach, the leading twist light-cone distribution amplitudes, \phi_M(u)…

High Energy Physics - Phenomenology · Physics 2013-05-30 Chien-Wen Hwang

We project onto the light-front the pion's Poincare'-covariant Bethe-Salpeter wave-function, obtained using two different approximations to the kernels of QCD's Dyson-Schwinger equations. At an hadronic scale both computed results are…

Nuclear Theory · Physics 2015-06-12 Lei Chang , I. C. Cloet , J. J. Cobos-Martinez , C. D. Roberts , S. M. Schmidt , P. C. Tandy

We determine the values of the one- and two-loop low energy constants appearing in the SU(2) Chiral Perturbation Theory calculation of pion-pion scattering. For this we use a recent and precise sum rule determination of some scattering…

High Energy Physics - Phenomenology · Physics 2015-06-05 J. Nebreda , J. R. Pelaez , G. Rios

In the paper, we have carried out research on the $D\to\pi$ decay process. We employ two different currents to study the $D\to\pi$ transition form factors (TFFs) by using the light-cone sum rule within the framework of chiral current…

High Energy Physics - Phenomenology · Physics 2026-03-18 Xiu-Fen Wang , Hai-Jiang Tian , Yin-Long Yang , Long Zeng , Hai-Bing Fu

We revisit the calculation of the strong couplings $D^*D\pi$ and $B^*B\pi$ from the QCD light-cone sum rules using the pion light-cone distribution amplitudes. The accuracy of the correlation function, calculated from the operator product…

High Energy Physics - Phenomenology · Physics 2021-04-28 Alexander Khodjamirian , Blaženka Melić , Yu-Ming Wang , Yan-Bing Wei

In my talk I discuss the theoretical and experimental status of the pion distribution amplitude (DA). I show that the QCD sum rule method with nonlocal condensates (NLC) for the pion DA gives us admissible sets (bunches) of DAs for each…

High Energy Physics - Phenomenology · Physics 2007-05-23 Alexander P. Bakulev

We present our preliminary results on the lowest moment <x> of quark distribution functions of the pion using two flavor dynamical simulations with Wilson twisted mass fermions at maximal twist. The calculation is done in a range of pion…

High Energy Physics - Lattice · Physics 2019-08-13 Rémi Baron , Stefano Capitani , Jaume Carbonell , Karl Jansen , Zhaofeng Liu , Olivier Pène , Carsten Urbach

In this paper, we calculate the scalar $a_0(980)$-meson leading-twist wavefunction by using light-cone harmonic oscillator model (LCHO). In which the model parameters are determined by fitting the $\xi$-moments…

High Energy Physics - Phenomenology · Physics 2023-08-16 Zai-Hui Wu , Hai-Bing Fu , Tao Zhong , Yu Chen , Ya-Hong Dai

We give a continuum limit value of the lowest moment of a twist-2 operator in pion states from non-perturbative lattice calculations. We find that the non-perturbatively obtained renormalization group invariant matrix element is <x>_{RGI} =…

High Energy Physics - Lattice · Physics 2015-06-25 M. Guagnelli , K. Jansen , F. Palombi , R. Petronzio , A. Shindler , I. Wetzorke

We investigate the leading-twist light-cone distribution amplitudes for the pion and kaon based on the gauge-invariant nonlocal chiral quark model from the instanton vacuum in the presence of external axial-vector currents. We find that the…

High Energy Physics - Phenomenology · Physics 2008-11-26 Seung-il Nam , Hyun-Chul Kim

The improved light-cone distribution amplitudes (LCDAs) of the $\Lambda$ baryon are examined on the basis of the QCD conformal partial wave expansion approach. The calculations are carried out to the next-to-leading order of conformal spin…

High Energy Physics - Phenomenology · Physics 2014-09-16 Yong-Lu Liu , Chun-Yu Cui , Ming-Qiu Huang

The $B^*B\pi$ and $D^*D\pi$ couplings have previously been derived from a QCD light-cone sum rule in leading order. Here, we describe the calculation of the $O(\alpha_s)$ correction to the twist 2 term of this sum rule. The result is used…

High Energy Physics - Phenomenology · Physics 2009-10-31 A. Khodjamirian , R. Rückl , S. Weinzierl , O. Yakovlev

We analyze $F_\pi(Q^2)$ and $F_{P\gamma}(Q^2)$, $P=\pi,\eta,\eta'$, within the local-duality (LD) version of QCD sum rules, which allows one to obtain predictions for hadron form factors in a broad range of momentum transfers. To probe the…

High Energy Physics - Phenomenology · Physics 2012-02-14 Irina Balakireva , Wolfgang Lucha , Dmitri Melikhov

Considering, as a limit case, an approximately flat pion distribution amplitude, which is determined from the hardest, in momentum space, solution of the Bethe-Salpeter equation for the pion wave function, we compute the pion transition…

High Energy Physics - Phenomenology · Physics 2020-01-22 D. A. Fagundes , E. G. S. Luna , A. A. Natale , M. Pelaez

The comparison of the theoretical and experimental determinations of the anomalous magnetic moment of the muon $(g-2)_\mu$ constitutes one of the strongest tests of the Standard Model at low energies. In this article, we compute the leading…